Conditioning of granular potash



June 7, 1966 R. E. SMITH ETAL 3,254,762

CONDITIONING OF GRANULAR POTASH Filed Feb. 19, 1962 OIL 6 BRINE COARSECLEANEDG DESLlMED f 8 7 CONCENTRATE ORE DRAINAGE FLOTATION l2 TAILINGST0 BRINE CLARIFICATION BRINE 9 COARSE 7 CONCENTETE q 7 FLOTATION l2TAILINGS T0 BRINE CLARIFICATION INVENTOR.

RANDAL E. SMITH CLARENCE W. EGBOM Attorneys of potash flotation.

United States Patent 3,254,762 CONDITIONING 0F GRANULAR POTASH Randal E.Smith and Clarence W. Egbom, Carlsbad, N. Mex., assignors to PotashCompany of America, Carlsbad, N. Mex., a corporation of Colorado FiledFeb. 19, 1962, Ser. No. 174,108 17 Claims. (Cl. 209-2) This inventionrelates to the reagent conditioning of coarse sylvite ores andparticularly to an improved method of conditioning such ores prior toflotation.

In the Carlsbad basin potash ores consisting principally of sylvinite,which is a mechanical mixture of sylvite and halite with clay and tracesof other minerals, are generally upgraded by the flotation process. Theflotation process 3,254,762 Patented June 7, 1966 v we economical andefficient preparation or conditioning of coarse potash ores forflotation treatment which provides a highly efficient flotationconcentration of larger particles.

A further object of our invention is to provide a rapid and eflicientfilming or coating of coarse potash ore particles without appreciablesize reduction of particles by consists of grinding; sizing; scrubbing;desliming; dey watering, which includes removal of brine; conditioningwith reagents; and flotation of the sylvite fraction by air bubbleattachment.

Initial sizing is generally performed by dry screening into a coarsefraction of about -6 mesh and a standard fraction of minus 20 mesh(Tyler mesh size). The coarse and standard fractions are usually treatedseparately and this invention is directed primarily to the treatment ofthe coarse fraction.

The reagent conditioning of coarse sylvite ores is a I mixing operationin which amine and oil reagents are added to a pulp following scrubbingand slime removal operations. The amine reagent is well known in the artThe preferred reagent for coarse flotation is in general based onoctadecyl amine, but consists of mixtures prepared from natural fatswith or without further hydrogenation. A common reagent is known astallow amine, and the common reagent for coarse flotation is ahydrogenated tallow amine. This reagent is preferably added as anemulsion prepared by partial neutralization with acid.

The oils may be crude residues from petroleum refining and are generallyheavy or viscous in character. Such viscous reagents are diflicult todistribute thoroughly in the slurry. It is recognized in the industrythat gentle mixing for as short a time as possible is desirable incoarse sylvite conditioning, since increasing the time or intensity ofthe mixing or both may result in further slimes release or theproduction of fine particles by attrition, both of which consumeadditional reagent and have other undesirable effects. However, in manyinstances, gentle mixing in conventional fashion does not provide thethor ough reagent distribution necessary for effective flotation ofcoarse potash.

It has now been found that reagents can be added in the presence ofconsiderable brine, provided the excess brine is removed before the pulpis fed to the flotation cell. We have found that the best results areattained when the reagents are added to a pulp containing about 15% ormore brine by weight. Gentle mixing following brine removal has alsobeen found to be effective in improving flotation efliciency,

Substantial improvements in flotation efliciency which may be observedas lower reagent rates or larger particles floated or both, are madepossible by use of this method. It is particularly advantageous at lowrates of reagent use.

It is an object of our invention to provide a'simple, economical andeflicient preparation or conditioning of potash ores for flotationtreatment which provides a low rate of reagent use in highly eflicientflotation concentration.

Another object of this invention is to provide a simple,

attrition.

Still another object of this invention is to provide a simple,economical and efficient preparation or conditioning'of coarse potashores which provides a highly eflicient flotation concentration withoutuse of a clay blinding re agent in the treatment.

The practice of our invention will be described with ref erence to theaccompanying drawings. In the drawings:

FIG. 1 is a typical flow sheet for the practiceof our inventionutilizing a single reagent mixing stage; and

FIG. 2 is a typical flow sheet for the practice of our inventionutilizing a two-stage mixing of reagent.

The flow'sheet of FIG. 1 depicts a typical practice where only a singlestage mixing treatment is required. As shown, cleaned and deslimed orefrom a suitable source of supply 3 is delivered into a mechanical mixer4, preferably a horizontal rotary drum providing a retention time offrom about 20 seconds to about 1 minute. An amine collector reagent 5and an oil 6, if desired, are fed into mixer 4 in controlled quantities.A major portion of thebrine is removed from the ore, usually by gravitydraining as on screen 7, and the separated brine may be returned tobrine clarification.

The conditioned ore after brine removal is delivered as the feed 8 to aflotation stage 9 in which brine of the ore 10 is provided as thecarrier vehicle in the flotation action. Coarse potash collects on thesurface of the brine and is removed as a concentrate at 11, while theflotation tailings are removed as indicated at 12. Both concentrate and.tailings may be further processed as known in the art.

The circuit shown in FIG. 2 is essentially the same as the one justdescribed, except for the two-stage mixing. After initially mixing atstage 4 and dewatering as indicated at 7, the ore is fed into a secondmixer 4 also pro It is understood when referring to brine, we mean asolution prepared by contact with the ore, and which is approximatelysaturated with NaCl and KCl and which is used as the fluid medium in thesylvite ore dressing process.

Dewatering as used herein designates a liquid-solids separation-in whichassociated brine is separated from the ore.

In practicing the invention the coarse sylvite ore is prepared bycrushing and screening the ore to obtain a particle size range that issubstantially 6 +20 mesh. The ore is slurried in brine and scrubbed torelease clay slimes. The pulp is then deslimed by washing with cleanbrine to remove all free slimes, leaving a clean pulp which is ready forreagent conditioning.

In our method, the clean pulp is delivered to the conditioner at a pulpdensity from 50% to solids, preferably about 65% solids. Theconditioning vessel is preferably a revolving horizontal drum, turningat a rate to give gentle but thorough mixing. The amine reagent and theoil are added and the pulp is mixed for /2 to 1 minute, with the shortertime usually sufficient for complete reagent distribution. If theconditioner revolves too rapidly or if the retentiontime is too long,further slimes may be released causing a greater demand for reagents.

The presence of brine in this part of the conditioning formed on thecarefully mixed lot of sylvinite ore from process is of value as alubricant to further gentle the the Carlsbad, New Mexico basin. Noauxiliary reagents mixing action and to distribute small quantities ofreagents such as starch or guar were used. through the pulp. Table Icontains typical examples of the effect of re- The pulp is thenpartially dewatered. This can be ac- 5 moving brine after initial mixingwithout further mixing.

TABLE I Reagent Rates, Percent 1st Mix Final Lb./Ton Temp., TailingsPercent Pulp Time, Drain Pulp F. Grade, Per- KC] Density Sec. Densitycent K20 Recovery Amine Oil 65 60 No 65 0. 1 0. 6 77 11.01 64. e5 60 Yes93 0. 1 0. 6 77 4. 28 87.6 75 60 No- 75 0. 06 0. 8 85 6. 77 76.3 75 60Yes 95 0. 06 0. 8 85 3. 0a 89. 9 50 60 No 50 0. 06 0. 8 85 9. 00 66. 750 60 Yescomplished by draining by gravity through a screen or by 20Table II illustrates the efiect of draining to different suction orother mechanical means. The pulp is drained pulp densities after initialmixing at uniform low pulp to 85% solids or above with the preferreddensity being densities.

TABLE II Reagent Rates, Percent 1st Mix Final Lb./Ton Temp, TailingsPercent Pulp Time, Drain Pulp F. Grade, Per- K01 Density Sec. Densitycent K10 Recovery Amine Oil above 90%. This may take from 20 seconds toover 1 35 Table III illustrates the advantage gained in a typical minuteby gravity depending on the depth of the ore bed, test in which a periodof mixing was given the ore folreagent rates, particle size, etc. lowingdraining of the brine used in the mixing step.

TABLE III Reagent Rates, Percent 1st 1st Mix 2nd Mix Final Pulp Lb./TonTemp., 'lailings Percent KCl Pulp Density Time, Sec. Drain Time, See.Density F. Grade, Per- Recovery cent K10 Amine Oil 65 Yes 93 0. 1 0. 677 4. 28 87. 6 30 Yes 30 93 0. 1 0. 6 77 2.88 91. 9

As the brine is drained from the pulp the solids may 50 Table IVcontains a number of general examples showbe mixed gently. Flotation ofthe prepared ore provides ing the advantage of draining after initialmixing over improved recovery over that at identical reagent rates notdraining at various levels of reagent use, different without draining,or, comparble flotation is achieved at starting pulp densities and attwo different temperatures.

TABLE IV Reagent Rates, Percent 1st 1st Mix 2nd Mix Final Pulp Lb./T0nTemp, Tailings Percent KC] Pulp Density Time, Sec. Drain Time, See.Density F. Grade, Per- Recovery cent K20 Amine Oil substantially reducedreagent rates when the reagentized Table V illustrates the combinedeffect of initial mixore is dewatered. ing at low pulp density, followedby draining and further To illustrate the advantages of the invention,the followmixing over conventional conditioning. Results are ingflotation results are tabulated. All tests were per- 75 shown at twodifferent reagent rates.

TABLE v Reagent Rates, Percent 1st 1st Mix 2nd Mix- Final Pulp LbJTonTemp., Taillngs Percent K01 Pulp Density Time, Sec. Drain Time, Sec.Density F. Grade, Per- Recovery cent K20 Amine Oil 95 60 N o 95 0. 1 0.8 90 7. 18 76. 74 30 Yes 3O 93 0. 1 0.8 90 4. 22 86. 2 95 60 No 95 0. 20.8 90 2. 91 90. 7 74 30 Yes 30 93 v 0. 2 0.8 90 2. 64 91. 5

We have thus found a distinct improvement in conditioning of these oresby distributing the reagent in a wet pulp, followed by draining ofltheexcess brine.

Since these factors will vary with reagent rates, with temperature, withtype of reagent, the times suggested are for explanation only, and we donot intend to be limited by them. Changes and modifications may beavailed of within the spirit and scope of the invention as defined inthe hereunto appended claims.

What We claim is:

1. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and desilimedpotash ore in a size range of about minus 6 plus 20 mesh and a brinecarrier and having a pulp density of about 50% to 85% solids,introducing an amine collector reagent into said pulp, mixing the pulpand reagent so introduced, then moving the pulp and reagent mixturedirectly into a brine removal stage in which a portion of the brine isremoved to establish a pulp density of at least 85 solids and whereinreagentized ore surfaces are exposed to atmosphere, and passing thereagentized ore after brine removal without further treatment into aflotation concentration stage.

2. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85 solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced without material attrition, then removing the pulp andreagent mixture directly into a brine removal stage in which a portionof the brine is removed to establish a pulp density of at least 85%solids and wherein reagentized ore surfaces are exposed to atmosphere,and passing the reagentized ore after brine removal without furthertreatment into a flotation concentration stage.

3. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a.

pulp density of about 50% to 85% solids, introducing an amine collectorreagent into said pulp, mixing the pulp and reagent so introduced forfrom about 20 seconds to about one minute, then'moving the pulp andreagent mixture directly into a brine removal stage in which a portionof the brine is removed to establish a pulp density of at least 85solids and wherein reagentized ore surfaces are exposed to atmosphere,and passing the reagentized ore after brine removal Without furthertreatment into a flotation concentration stage.

4. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and desilimedpotash ore in a size range of about minus 6 plus 20 mesh and a brinecarrier and having a pulp density of about 50% to 85 solids, introducingan amine collector reagent into said pulp, mixing the pulp and reagentso introduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of more than 85% solids and wherein reagentizedore surfaces are exposed to atmosphere, and passing the reagentized oreafter brine removal without further treatment into a flotationconcentration stage.

and reagent so introduced for about one minute, then moving the pulp andreagent mixture directly into a brine re moval stage in which a portionof the brine is removed to establish a pulp density of at least solidsand wherein reagentized ore surfaces are exposed to atmosphere, andpassing the reagentized ore after brine removal without furthertreatment into .a flotation concentration stage.

6. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85 solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine drainage stage in which a portion of the brine is removed toestablish a pulp density of at least 85% solids and wherein reagentizedore surfaces areexposed to atmosphere, and passing the reagentized oreafter brine removal without further treatment into a flotationconcentration stage.

7. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% 'to 85 solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of about solids and wherein reagentized oresurfaces are exposed to atmosphere, and passing the reagentized areafter brine removal without further treatment into a flotationconcentration stage.

' 8. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85 solids, introducing anamine collector reagent into said 'pulp, mixing the pulp and reagent sointroduced without blinding reagent addition, then moving the pulp andreagent mixture directly into a brine removal stage in which a portionof the brine is removed to establish a pulp density of at least 85solids and wherein reagentized ore surfaces are exposed to atmosphere,and passing the reagentized ore after brine removal without repulpinginto a flotation concentration stage.

9. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50%to 85 solids, introducing an aminecollector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of at least 85% solids and wherein reagentizedore surfaces are exposed to atmosphere, and

7 passing the reagentized ore after brine removal and a said establisheddensity into a flotation concentration sage.

10. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and -a brine carrierand having a pulp density of about 50% to 85% solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of at least 85% solids and wherein reagentizedore surfaces are exposed to atmosphere, and passing the reagentized oreafter final mixing without further treatment into -a flotationconcentration stage.

11. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85 solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced without blinding reagent addition, then moving the pulp andreagent mixture directly into a brine removal stage in which a .portionof the brine is removed to establish a pulp density of at least 85%solids and wherin reagentized ore surfaces are exposed to atmosphere,subjecting the ore and said reagent to additional mixing after brineremoval, and passing the reagentized ore after final mixing directlyinto a flotation concentration stage.

12. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85% solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced for from about 20 seconds to about one minute, then movingthe pulp and reagent mixture directly into a brine removal stage inwhich a portion of the brine is removed to establish a pulp density ofat least 85% solids and wherein reagentized ore surfaces are exposed toatmosphere, mixing the ore at said density with said reagent for from 20seconds to about one minute, and passing the reagentized ore after finalmixing without further treatment into a flotation concentration stage.

13. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85% solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of at least 90% solids and wherein reagentizedore surfaces are exposed to atmosphere, subjecting the ore and saidreagent to additional mixing after brine removal, and passing thereagentized ore after final mixing without further treatment into aflotation concentration stage.

14. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about solids, introducing an aminecollector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine removal stage in which a portion of the brine is removed toestablish a pulp density of at least solids and wherein reagentized oresurfaces are exposed to atmosphere, and passing the reagentized oreafter brine removal without further treatment into a flotationconcentration stage.

15. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 65% solids, introducing an aminecollector reagent into said pulp, mixing the pulp and reagent sointroduced, then moving the pulp and reagent mixture directly into abrine drainage stage in which a portion of the brine is removed toestablish a pulp density of at least solids and wherein reagentized oresurfaces are exposed to atmosphere, and passing the reagentized oreafter brine drainage without further treatment into a flotationconcentration stage.

16. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85% solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced at a first mixing stage, then moving the pulp and reagentmixture directly into a brine removal stage in which sufiicient freebrine is removed to establish a pulp density of at least 85 solids andwherein reagentized ore surfaces are exposed to atmosphere, moving thereagentized ore after brine removal through a second mixing stage, andpassing the reagentized ore after final mixing and at said establisheddensity into a flotation concentration stage.

17. A method of preparing potash ores for a flotation treatment,consisting of the steps of forming a pulp of cleaned and deslimed potashore in a size range of about minus 6 plus 20 mesh and a brine carrierand having a pulp density of about 50% to 85 solids, introducing anamine collector reagent into said pulp, mixing the pulp and reagent sointroduced at a first mixing stage, then moving the pulp and reagentmixture directly into a brine-removal stage in which suificient freebrine is removed to establish a pulp density of at least 85% solids andwherein reagentized ore surfaces are exposed to atmosphere, moving thereagentized ore after brine removal through a second mixing stage formixing with said reagent for from about 20 seconds to one minute, andpassing the reagentized ore after final mixing and at said establisheddensity into a flotation concentration stage.

References Cited by the Examiner UNITED STATES PATENTS 2,950,007 8/1960Smith 209-116 FRANK W. LUTTER, Primary Examiner.

ROBERT A. OLEARY, Examiner.

1. A METHOD OF PREPARING POTASH ORES FOR A FLOTATION TREATMENT,CONSISTING OF THE STEPS OF FORMING A PULP OF CLEANED AND DESILIMEDPOTASH ORE IN A SIZE RANGE OF ABOUT MINUS 6 PINS 20 MESH AND A BRINECARRIER AND HAVING A PULP DENSITY OF ABOUT 50% TO 80% SOLIDS,INTRODUCING AN AMINE COLLECTOR REAGENT INTO SAID PULP, MIXING THE PULPAND REAGENT TO INTRODUCED, THEN MOVING THE PULP AND REAGENT MIXTUREDIRECTLY INTO A BRINE REMOVAL STAGE IN WHICH